The main purpose of this research was to understand the nature of social capital in a Thai ruralcommunity and the role of social capital for community development by analyzing two characteristicsof social capital: cognitive social capital and structural social capital. In addition, the transformationprocess of social capital in these two characteristics into social capital practice was observed. The research focused on existing social capital and the social actors who transform social capital into social capital practice as well as the expression of social capital practice in various forms. The research used qualitative research methods, participatory observation and in-depthinterview, to study one village in the north-eastern region of Thailand. The village was selected bypurposive sampling on the precondition that the village had long been developed and that there weremany local organizations for the development movement. The research found that the explanation of social capital in its two characteristics, cognitivesocial capital and structural social capital, cannot explain social capital in a Thai village because thisexplanation sees social capital as stagnant which cannot play a role in the community development. Inorder to use social capital in community development, there must be social actors to transform socialcapital into social capital practice. These actors are the village leaders who are the products of thevillage history in development ideology and the engagement in many activities for the communitydevelopment. Social capital of the village which is transformed into social capital practice is the value systemin respect to the old people and the village leaders, the kindred system, the respect to the same Pee-Pu-Ta and the social network. The social capital practice is based on the norm of trust, reciprocity and goodrelationship either between the village’s leaders and the villagers or among the village leaders. What ismore, it was found that economic capital plays a role in supporting the transformation of social capitalinto social capital practice. The research also found that social capital practice has produced new social capital based onexisting social capital in the village through new signs. For example, the self-supporting discourse (Het-Yu-Het-Kin), the community money, the farmer school, the culture school, the community bank, therice celebration ceremony and the village’s rice mill. These new types of social capital are newstructures of associational life which are reproduced with new meaning in accordance with socio-cultural dynamics of change. Another interesting finding is that participation of the villagers in the form of civil societyhelps facilitate the transformation of social capital into social capital practice and production of newsocial capital based on the existing social capital. As for suggestions, this research suggests that participation of the villagers in the form of civilsociety should be supported. Networks of many development movements at the community level shouldalso be supported for mutual learning between villagers and close relationships between villagers in onevillage and those in other villages. Attention to new signs should also be given to produce new socialcapital. In case any organization would like to use social capital for community development, attentionshould also be given to equal access of villagers to social capital.